Adjustable contact system



Dec. 18, 1962 F. KOEHLER 3,069,515

ADJUSTABLE CONTACT SYSTEM Filed April 8, 1960 f6 45 34 32 35 42 I j 50 /2 E g\ l (/j X I E g. 2

INVENTOR Fred Kae/r/er;

ATTORNEYS United States atent O vania Filed Apr. 8, 1960, Ser. No. 20,980 5 Claims. (Cl. 20038) This invention relates to an electric watch or clock, and more particularly relates to a commutating or contact system for such a watch or clock.

In Koehler Patent No. 2,662,366, there is shown an electric Watch or clock wherein a balance wheel is driven by an armature oscillating between a pair of pole pieces which are periodically magnetized by electromagnets connected in a circuit with a primary cell. The oscillating balance wheel is connected through a suitable indexing system to drive the train of the watch or clock and the indexing motion is also utilized to periodically close a set of commutating contacts which eifect the energization of the electromagnets to impulse the balance wheel. The duration of energization of the electromagnets and the concomitant duration of the impulse to the balance wheel have an efiect'on the motion of the balance wheel, and therefore upon the isochronal characteristics of the watch or clock. As the contacts wear during normal usage of the watch or clock, this period of contact tends to change and some adjustment of the contact system ultimately becomes necessary.

In the contact system shown in the aforementioned Koehler Patent No. 2,662,366, a toothed index wheel is advanced one tooth for each oscillation of the balance Wheel, and this motion of the index Wheel is utilized to move a spring contact arm each time that a tooth passes by a cam carried thereby. The spring contact arm carries at the end thereof a contact element which is arranged to electrically contact a stationary contact element and thereby complete the circuit to the electromagnet. After the watch or clock has been in use for a period of time, the size and surface condition of the contact elements are changed and it becomes necessary to adjust the spacing therebetween in order to retain the initial isochronal characteristics. In this type of contact system, which is explained in detail in the Koehler patent, it has been customary to effect this adjustment by simply bending the contact spring to regain the initial isochronal action. While this is effective, it will be appreciated that it entails a somewhat critical adjustment, and necessitates some experience on the part of the adjusting technician.

According to the present invention, it has been found that it is possible to construct a watch or clock having a contact system of the type originally described in the Koehler patent wherein the criticality of adjustment and the necessity of prior experience is substantially eliminated. As a feature of the invention, the stationary contact element is mounted for movement in such a way that an indicator attached thereto can be moved through a relatively large indication in order to bring about a slight change in the position of the stationary contact element. In this way, the criticality of contact is largely eliminated, and it becomes possible for a relatively inexperienced clock repairman to return the watch or clock to its original isochronal characteristics without danger of damage thereto.

It is accordingly a primary object of the present invention to provide an electric watch or clock utilizing a. commutating contact system which is characterized by ease and simplicity of adjustment in order to regulate the duration of contact.

It is another object of the invention to provide an improved battery operated watch or clock wherein the "ice balance wheel drives an index gear which in turn moves a contact spring arm to effect periodic energization of electromagnets which power the oscillation of the balance wheel, characterized by the improvement which permits simple uncritical adjustment of the duration of contact of the spring arm with a stationary contact.

It is still another object of the invention to provide an improved battery operated watch or clock containing a driving arrangement which utilizes a commutating contact system which includes an adjustment for regulating the duration of contact to extremely accurate limits.

It is a still further object of the invention to provide a battery operated watch or clock utilizing a commutating contact system and including an adjustment which controls the duration of contact to an extremely accurate degree through movement of an indicating member through a relatively large scale indication.

These and further objects and advantages of the invention will become more apparent upon reference to the following specification and claims and appended drawings wherein:

FIGURE 1 is a partial plan view of a watch or clock showing a commutating contact system and index system constructed according to the present invention; and

FIGURE 2 is a partial vertical elevation, partially in section showing the contact system of FIGURE 1.

The contact system of this invention may be utilized with any electric watch or clock wherein periodic contact is utilized, but, for purposes of convenience, is de scribed herein in connection with a watch or clock of the type disclosed and described in detail in Koehler Patent No. 2,662,366. In that patent, a balance wheel is sustained in oscillation by means of a magnetic armature connected to the balance staff and periodically attracted to a pair of pole pieces which are associated with a pair of electromagnets. The electromagnets are periodically energized by the contact system of the watch or clock and this system in turn is associated with the indexing mechanism. In the Koehler patent there is shown an indexing mechanism wherein a spring end extending substantially parallel to the balance staff periodically engages teeth on an index gear to drive that gear as the balance wheel and the spring end oscillate.

Referring to FIGURE 1, the balance staff in a watch or clock of the type shown in Koehler Patent No. 2,662,366 is indicated at 10 and is mounted in the pillar plate 12 in conventional fashion. The balance stalfcarries a flange 14 having a slot 16 therein which receives the end 18 of a coil spring having its other end attached to the balance staff. The end 18 extends parallel to the balance staif and is retained in the slot 16 by means of a ring 20. Spring end 18 engages the teeth 22 of an index wheel generally indicated at 24, and. is adapted to drive the index wheel in a clockwise direction. The index wheel in turn drives the train 26.

As the balance staff 10 oscillates in a counterclockwise direction, as indicated by the arrow in FIGURE 1, the spring end 18 engages the radial surface of the tooth 28. The spring end 18 is at this time restrained by the ring 20 and therefore as the balance staff continues to oscillate, the index wheel 24 is driven in a clockwise direction. During reverse oscillation of the balance staff, the spring end 18 engages the tangential side of a tooth such as tooth 28. In this instance, however, the spring end is free to move inwardly in the slot 16 and causes no motion of the index wheel 24.

A contact spring 30 is mounted to the pillar plate by means of a suitable mounting assembly, not shown, which is insulated from the pillar plate, and extends past the index wheel 24. A carbaloy cam 32 is carried intermediate the ends of contact spring 30 by means of a U- shaped saddle 34 which is welded, soldered or brazed to' the spring. The cam 32 engages the teeth 22 of the index wheel 24. The contact spring 30 is so tensioned at its point of mounting as to urge the cam 32 into engagement with the teeth 22 of the index wheel 24 so that the cam serves as a detent holding the index wheel in a fixed position until it is moved by the spring end 18 associated with the balance staff as previously described.

The outer end 36 of contact spring is provided with bifurcations 38 and 40 which carry silver contacts 42 and 44. A mounting pin 46 is friction fitted in the pillar plate '12 and carries a fibre or other insulating post 43 which is eccentrically mounted thereon. The post 48 is friction fitted on the pin 46 so as to retain any positional setting which is established. A silver contact sleeve 50 is secured around the post 48 and is connected by a conductor 52 to the battery for energizing the electromagnetic drive mechanism of the watch or clock. An elongated indicator pointer 54 is also frictionally mounted about the post 48 and terminates in a pointed end 56. The end 56 cooperates with suitable indicia 58 to provide an indication of the setting of the contact mechanism.

As the balance wheel oscillates in a counterclockwise direction and the coil end 18 drives the index wheel 24 clockwise, the tooth engagement with the cam 32 causes the cam to move outwardly to the left in FIGURE 1 to thereby drive contacts 42 and 44 at the end of contact spring 36 into engagement with the contact sleeve 50 on post 48. This contact occurs as the balance wheel is encountering maximum resistance in its movement of index wheel 24 and at that time an electrical impulse introduces mechanical energy into the balance wheel to drive the tooth in engagement with cam 32 past the cam and thereby advance the index wheel one tooth position. As the cam 32 passes the radial end of the tooth which it contacts, it drops into engagement with the tangential surface of the following tooth, thereby breaking the contacting engagement between contacts 42 and 44 and sleeve 50. As the balance wheel oscillates in the return or clockwise direction, the coil end 18 simply rides inwardly in slot 16 and does not cause further movement of the index wheel 24 so that no contact occurs.

It will be apparent that with this arrangement a rotation of the indicator 54 in a clockwise direction through a relatively large scale indication of indicia 58 will cause an almost imperceptible decrease in the distance between con tacts 42 and 44 and contact sleeve 50. This shortening of the gap between contact members increases the duration of contact upon oscillation of the balance staff and advancement of the index wheel, and increases motion.

Conversely, a movement of the indicating member 54 in p produces a controllable variation in the motion of the balance Without the necessity of attempting to bend the contact spring 30. By knowledge of proper motion for the timepiece, a Watch repairman relatively unskilled with battery operated timepieces is enabled to properly adjust the timepiece Without danger of damage thereto. If desired, a chart may be provided to indicate the proper setting of the indicator 54 as the timepiece ages.

It will be apparent from the foregoing description of the contact system of this invention that provision is made for adjustment of the motion of the timepiece through the use of an adjustable contact system which is quite simple in construction and susceptible of maintenance by watch technicians who are relatively unskilled with battery operated timepieces. The construction is economical, capable of pre-calibration, and presents new contact surfaces on the contact sleeve as the timepiece ages. While the contact system has been described in connection with a particular battery operated timepiece, it will be apparent that it is susceptible of use in any electric timepiece wherein an index wheel is caused to close the gap between a pair of spaced contact members.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to he considered in all respects as illustrative and not restrictive, the scope of the, invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a battery operated timepiece having a frame, a toothed gear and an enlongated spring member each mounted on said frame, said spring member having a cam surface in engagement with the teeth of said gear so that said spring member is caused to move toward and away from said gear as said gear is advanced, a first electrical contact mounted on said spring member, a mounting pin carried by said frame of said timepiece, and an arcuate electrical contact eccentrically mounted on said pin so that rotation of said arcuate contact about said pin varies the maximum gap between said first and arcuate contacts.

2. In a bat-tery operated timepiece having a frame, a toothed gear in engagement with a cam surface on an elongated member, a first electrical contact carried by said member, a pin carried by said frame of said timepiece, an insulating post eccentrically mounted on said pin, and an electrical contact sleeve carried by said post so that rotation of said post on said pin varies the maximum gap between said first contact and said contact sleeve.

3. In a battery operated electric timepiece having a frame, a toothed gear in engagement with a cam surface on an elongated member, an electrical contact carried by said member, a pin mounted in said frame of said timepiece, an insulating post eccentrically mounted on said pin, an electrical contact sleeve mounted around said post, an actuator arm attached to said post for moving said post about said pin, and indicia associated with said actuator arm so that movement of the portion of the actuator arm opposite said indicia causes an adjustment in the maximum distance between said Contact and said sleeve.

4. An adjustable contact system for abattery operated timepiece comprising: a frame for said timepiece; a toothed gear mounted on said frame; an elongated spring member; said spring member being coupled to said toothed gear so that said spring member reciprocates as said gear advances; a first electrical contact mounted on one end of said spring member; an arcuate contact eccentrically mounted on said frame spaced from said first contact; said arcuate contact being adjustable toward and away from said first contact by angular movement of an indicating member through a distance considerably greater than the resultant adjustment of said arcuate contact so that said adjustment of said arcuate member varies the maximum space between said first and arcuate contacts.

5. An adjustable contact system in accordance with claim 4 wherein said spring member is coupled to said toothed gear by a cam member and said arcuate contact is eccentrically mounted on said frame by a transverse mounting pin.

References Cited in the file of this patent UNITED STATES PATENTS ,083 Jamin Jan. 27, 1920 ,050 Reichart May 9, 1922 70 Wagner July 8, 1924 .603 Miller Feb. 13, 1940 66 Koehler Dec. 15, 1953 ,269 Buck et a1. June 25, 1957 2,820,358 Tompkins Jan. 21, 1958 ,534 Beauclair Sept. 30, 1958 2. 3 Bensingler Sept. 1, 1959 

